Merge branch 'master' of https://github.com/brayo-pip/Go

Author: 0xbrayo

DIRECTORY.md

@@ -1,6 +1,9 @@
 
 ## Ciphers
   * [Caesarcipher](https://github.com/TheAlgorithms/Go/blob/master/ciphers/CaesarCipher.go)
+  * [Diffiehellmankeyexchange](https://github.com/TheAlgorithms/Go/blob/master/ciphers/diffieHellmanKeyExchange.go)
+  * [Rsacipher](https://github.com/TheAlgorithms/Go/blob/master/ciphers/RSAcipher.go)
+  * [Xorcipher](https://github.com/TheAlgorithms/Go/blob/master/ciphers/xorCipher.go)
 
 ## Data-Structures
   * Binary-Tree
@@ -20,6 +23,7 @@
 
 ## Dynamic-Programming
   * [Longest-Palindromic-Subsequence](https://github.com/TheAlgorithms/Go/blob/master/dynamic-programming/longest-palindromic-subsequence.go)
+  * [Longestcommonsubsequence](https://github.com/TheAlgorithms/Go/blob/master/dynamic-programming/longestCommonSubsequence.go)
   * [Matrix-Multiplication](https://github.com/TheAlgorithms/Go/blob/master/dynamic-programming/matrix-multiplication.go)
   * [Rod-Cutting](https://github.com/TheAlgorithms/Go/blob/master/dynamic-programming/rod-cutting.go)
 
@@ -48,4 +52,12 @@
   * [Topological Sort](https://github.com/TheAlgorithms/Go/blob/master/sorts/topological_sort.go)
 
 ## Strings
+  * Multiple String Matching
+    * [Ac](https://github.com/TheAlgorithms/Go/blob/master/strings/multiple%20string%20matching/ac.go)
+    * [Adac](https://github.com/TheAlgorithms/Go/blob/master/strings/multiple%20string%20matching/adac.go)
+    * [Sbom](https://github.com/TheAlgorithms/Go/blob/master/strings/multiple%20string%20matching/sbom.go)
   * [Naivestringsearch](https://github.com/TheAlgorithms/Go/blob/master/strings/naiveStringSearch.go)
+  * Single String Matching
+    * [Bom](https://github.com/TheAlgorithms/Go/blob/master/strings/single%20string%20matching/bom.go)
+    * [Horspool](https://github.com/TheAlgorithms/Go/blob/master/strings/single%20string%20matching/horspool.go)
+    * [Kmp](https://github.com/TheAlgorithms/Go/blob/master/strings/single%20string%20matching/kmp.go)

README.md

@@ -16,9 +16,9 @@ Also see: https://algorithmswithgo.com
 From [Wikipedia][bubble-wiki]: Bubble sort, sometimes referred to as sinking sort, is a simple sorting algorithm that repeatedly steps through the list to be sorted, compares each pair of adjacent items and swaps them if they are in the wrong order. The pass through the list is repeated until no swaps are needed, which indicates that the list is sorted.
 
 __Properties__
-* Worst case performance	O(n^2)
-* Best case performance	O(n)
-* Average case performance	O(n^2)
+* Worst case performance    O(n^2)
+* Best case performance    O(n)
+* Average case performance    O(n^2)
 
 ###### View the algorithm in [action][bubble-toptal]
 
@@ -30,9 +30,9 @@ __Properties__
 From [Wikipedia][insertion-wiki]: Insertion sort is a simple sorting algorithm that builds the final sorted array (or list) one item at a time. It is much less efficient on large lists than more advanced algorithms such as quicksort, heapsort, or merge sort.
 
 __Properties__
-* Worst case performance	O(n^2)
-* Best case performance	O(n)
-* Average case performance	O(n^2)
+* Worst case performance    O(n^2)
+* Best case performance    O(n)
+* Average case performance    O(n^2)
 
 ###### View the algorithm in [action][insertion-toptal]
 
@@ -43,9 +43,9 @@ __Properties__
 From [Wikipedia][merge-wiki]: In computer science, merge sort (also commonly spelled mergesort) is an efficient, general-purpose, comparison-based sorting algorithm. Most implementations produce a stable sort, which means that the implementation preserves the input order of equal elements in the sorted output. Mergesort is a divide and conquer algorithm that was invented by John von Neumann in 1945.
 
 __Properties__
-* Worst case performance	O(n log n)
-* Best case performance	O(n)
-* Average case performance	O(n)
+* Worst case performance    O(n log n)
+* Best case performance    O(n)
+* Average case performance    O(n)
 
 
 ###### View the algorithm in [action][merge-toptal]
@@ -56,9 +56,9 @@ __Properties__
 From [Wikipedia][quick-wiki]: Quicksort (sometimes called partition-exchange sort) is an efficient sorting algorithm, serving as a systematic method for placing the elements of an array in order.
 
 __Properties__
-* Worst case performance	O(n^2)
-* Best case performance	O(n log n) or O(n) with three-way partition
-* Average case performance	O(n^2)
+* Worst case performance    O(n^2)
+* Best case performance    O(n log n) or O(n) with three-way partition
+* Average case performance    O(n^2)
 
 ###### View the algorithm in [action][quick-toptal]
 
@@ -68,9 +68,9 @@ __Properties__
 From [Wikipedia][selection-wiki]: The algorithm divides the input list into two parts: the sublist of items already sorted, which is built up from left to right at the front (left) of the list, and the sublist of items remaining to be sorted that occupy the rest of the list. Initially, the sorted sublist is empty and the unsorted sublist is the entire input list. The algorithm proceeds by finding the smallest (or largest, depending on sorting order) element in the unsorted sublist, exchanging (swapping) it with the leftmost unsorted element (putting it in sorted order), and moving the sublist boundaries one element to the right.
 
 __Properties__
-* Worst case performance	O(n^2)
-* Best case performance	O(n^2)
-* Average case performance	O(n^2)
+* Worst case performance    O(n^2)
+* Best case performance    O(n^2)
+* Average case performance    O(n^2)
 
 ###### View the algorithm in [action][selection-toptal]
 
@@ -86,7 +86,7 @@ __Properties__
 
 ###### View the algorithm in [action][shell-toptal]
 
-### Time-Compexity Graphs
+### Time-Complexity Graphs
 
 Comparing the complexity of sorting algorithms (Bubble Sort, Insertion Sort, Selection Sort)
 
@@ -100,24 +100,24 @@ Comparing the complexity of sorting algorithms (Bubble Sort, Insertion Sort, Sel
 ![alt text][linear-image]
 
 From [Wikipedia][linear-wiki]: linear search or sequential search is a method for finding a target value within a list. It sequentially checks each element of the list for the target value until a match is found or until all the elements have been searched.
-  Linear search runs in at worst linear time and makes at most n comparisons, where n is the length of the list.
+  Linear search runs in at the worst linear time and makes at most n comparisons, where n is the length of the list.
 
 __Properties__
-* Worst case performance	O(n)
-* Best case performance	O(1)
-* Average case performance	O(n)
-* Worst case space complexity	O(1) iterative
+* Worst case performance    O(n)
+* Best case performance    O(1)
+* Average case performance    O(n)
+* Worst case space complexity    O(1) iterative
 
 ### Binary
 ![alt text][binary-image]
 
 From [Wikipedia][binary-wiki]: Binary search, also known as half-interval search or logarithmic search, is a search algorithm that finds the position of a target value within a sorted array. It compares the target value to the middle element of the array; if they are unequal, the half in which the target cannot lie is eliminated and the search continues on the remaining half until it is successful.
 
 __Properties__
-* Worst case performance	O(log n)
-* Best case performance	O(1)
-* Average case performance	O(log n)
-* Worst case space complexity	O(1) 
+* Worst case performance    O(log n)
+* Best case performance    O(1)
+* Average case performance    O(log n)
+* Worst case space complexity    O(1) 
 
 ----------------------------------------------------------------------------------------------------------------------
 
@@ -128,7 +128,7 @@ __Properties__
 In cryptography, a **Caesar cipher**, also known as Caesar's cipher, the shift cipher, Caesar's code or Caesar shift, is one of the simplest and most widely known encryption techniques.<br>
 It is **a type of substitution cipher** in which each letter in the plaintext is replaced by a letter some fixed number of positions down the alphabet. For example, with a left shift of 3, D would be replaced by A, E would become B, and so on. <br>
 The method is named after **Julius Caesar**, who used it in his private correspondence.<br>
-The encryption step performed by a Caesar cipher is often incorporated as part of more complex schemes, such as the Vigenère cipher, and still has modern application in the ROT13 system. As with all single-alphabet substitution ciphers, the Caesar cipher is easily broken and in modern practice offers essentially no communication security.
+The encryption step performed by a Caesar cipher is often incorporated as part of more complex schemes, such as the Vigenère cipher, and still has modern applications in the ROT13 system. As with all single-alphabet substitution ciphers, the Caesar cipher is easily broken and in modern practice offers essentially no communication security.
 ###### Source: [Wikipedia](https://en.wikipedia.org/wiki/Caesar_cipher)
 
 ### Transposition

ciphers/RSAcipher(Big).go

@@ -0,0 +1,128 @@
+package main
+
+import (
+	"math/big"
+	crypto"crypto/rand"
+	"strconv"
+	"fmt"
+)
+/*
+Care has been taken to uses cryptographic secure functions
+The primes numbers are 1024 bits which is as secure as u can get really
+crypto/rand library has been imported as crypto and not rand
+This import style will make it easier to spot all the cryptographic secure functions
+*/
+func main(){
+	p,_:= crypto.Prime(crypto.Reader,1024)
+	q,_:= crypto.Prime(crypto.Reader,1024)
+	if !(primeCheck(p)||primeCheck(q)){
+		//they are always prime, no worries
+		fmt.Println("These numbers ain't prime")
+	}
+	n := new(big.Int).Mul(p,q)
+	
+	one := big.NewInt(1)
+
+	delta := lcmBig(p.Sub(p,one),q.Sub(q,one))
+
+	e,_:= crypto.Prime(crypto.Reader,delta.BitLen())
+	d := big.NewInt(0)
+	d.ModInverse(e,delta)
+
+	cleartext := "Black Lives Matter, all lives can't matter until Black lives matter"
+	runes :=[]rune(cleartext)
+	ASCIIs :=toASCII(runes)
+	stringEncoded := stringEncode(ASCIIs)
+	bigNum, _ :=  new(big.Int).SetString(stringEncoded,0)
+	/*
+	TODO: check that bigNum is not larger than N if larger break
+	into two or more strings and encrypt separately
+	*/
+	fmt.Printf("Message to be encrypted: %v \n",cleartext)
+	fmt.Printf("ASCII encoded: %v\n",bigNum)
+	encrypted := encryptBig(bigNum,e,n)
+	fmt.Printf("ciphertext: %v \n",encrypted)
+	decrypted := decryptBig(encrypted,d,n)
+	fmt.Printf("Decrypted but still ASCII encoded: %v \n",decrypted)
+	decryptASCIIs := stringDecode(decrypted)
+	fmt.Printf("Plaintext (original message) :%v",toRune(decryptASCIIs))
+}
+
+func encryptBig(num *big.Int, privateExponent *big.Int, modulus *big.Int)*big.Int{
+	//encrypts by modular exponentiation
+	encrypted := new(big.Int).Exp(num,privateExponent,modulus)
+	return encrypted
+}
+
+func decryptBig(num *big.Int, publicExponent *big.Int, modulus *big.Int)*big.Int{
+	//decrypts by modular exponentiation
+	decrypted := new(big.Int).Exp(num,publicExponent,modulus)
+	return decrypted
+}
+
+func lcmBig(x *big.Int, y *big.Int)*big.Int{
+	//an lcm implementation for big.Int numbers
+	gcd := new(big.Int).GCD(nil,nil,x,y)
+	temp :=  new(big.Int).Mul(x,y)
+	lcm :=  new(big.Int).Div(temp,gcd)
+	return lcm
+}
+
+func primeCheck(prime *big.Int)bool{
+	//primality test
+	return prime.ProbablyPrime(256)
+}
+
+func toASCII(slice []rune)[]int{
+	//runs in O(n) where n = len(slice)
+	var converted []int
+	for _,v:= range slice{
+		converted = append(converted, int(v))
+	}
+	return converted
+}
+
+func toRune(slice []int)string{
+	//runs in O(n) where n = len(slice)
+	var str string
+	for _,v:= range slice{
+		str += string(v)
+	}
+	return str
+}
+
+func stringEncode(slice []int)string{
+	//encodes the ASCII to a string 
+	var out []string
+	for _,v := range slice{
+	if v<100 {
+		out =append(out,"0"+strconv.Itoa(v))
+		continue
+		}
+	out = append(out, strconv.Itoa(v))
+	}
+	var str string
+	for _,v := range out{
+		str += v
+	}
+	/*strips leading 0 if present to avoid conversion errors
+	*/
+	if str[0]== '0'{
+		str = str[1:]
+	}
+	return str
+}
+
+func stringDecode(decryptedBig *big.Int)[]int{
+	//decodes the number to string then ASCII values
+	str := decryptedBig.String()
+	if len(str)%3!=0{
+		str ="0"+str
+	}
+	var ASCII []int 
+	for i:=0; i<len(str); i+=3{
+		temp,_:= strconv.Atoi(str[i:i+3])
+		ASCII = append(ASCII,temp)
+	}
+	return ASCII
+}

dynamic-programming/longestCommonSubsequence.go

@@ -0,0 +1,49 @@
+// LONGEST COMMON SUBSEQUENCE 
+// DP - 4
+// https://www.geeksforgeeks.org/longest-common-subsequence-dp-4/
+
+package longestcommonsubsequence
+// package main 
+
+// import "fmt"
+
+func max(a,b int) int{
+	if a>b{
+		return a
+	}
+	return b
+}
+
+func longestCommonSubsequence(a string, b string, m int, n int) int{
+	// m is the length of string a and n is the length of string b 
+	
+	// here we are making a 2d slice of size (m+1)*(n+1)
+	lcs:= make([][] int, m+1)
+	for i:=0;i<=m;i++{
+		lcs[i] = make([]int, n+1)
+	}
+
+	// block that implements LCS
+	for i:=0;i<=m;i++{
+		for j:=0;j<=n;j++{
+			if i==0 || j==0{
+				lcs[i][j] = 0;
+			}else if a[i-1] == b[j-1]{
+				lcs[i][j] = lcs[i-1][j-1]+1
+			}else{
+				lcs[i][j] = max(lcs[i-1][j], lcs[i][j-1])
+			}
+		}
+	}
+	// returning the length of longest common subsequence
+	return lcs[m][n]
+}
+
+// func main(){
+// 	// declaring two strings and asking for input 
+	
+// 	var a,b string 
+// 	fmt.Scan(&a, &b)
+// 	// calling the LCS function 
+// 	fmt.Println("The length of longest common subsequence is:", longestCommonSubsequence(a,b, len(a), len(b)))
+// }

searches/binary_search.go

@@ -1,35 +0,0 @@
-/*
-	Binary search implementation in Go
-*/
-package main
-
-func binarySearch(array []int, target int, lowIndex int, highIndex int) int {
-	if highIndex < lowIndex {
-		return -1
-	}
-	mid := int((lowIndex + (highIndex-lowIndex)/2))
-	if array[mid] > target {
-		return binarySearch(array, target, lowIndex, mid)
-	} else if array[mid] < target {
-		return binarySearch(array, target, mid+1, highIndex)
-	} else {
-		return mid
-	}
-}
-
-func iterBinarySearch(array []int, target int, lowIndex int, highIndex int) int {
-	startIndex := lowIndex
-	endIndex := highIndex
-	var mid int
-	for startIndex < endIndex {
-		mid = int((startIndex + (endIndex-startIndex)/2))
-		if array[mid] > target {
-			endIndex = mid
-		} else if array[mid] < target {
-			startIndex = mid
-		} else {
-			return mid
-		}
-	}
-	return -1
-}